|By Mike Stone

(Reuters) - Democrat Kevin de Leon, president of the California State Senate, announced on Sunday he would run for the U.S. Senate in 2018, challenging incumbent Senator Dianne Feinstein.

The Los Angeles Democrat's announcement did not mention Feinstein, 84.

Feinstein, who was first elected to the Senate in 1992, is the top Democrat on the Senate Judiciary Committee and the first woman to hold that role. She is also a senior member of the Senate Select Committee on Intelligence and was the first woman to lead that panel, from 2009 through 2015.

Feinstein said last week that she would run for her fifth term.

She is the oldest U.S. senator but among several octogenarians, including Republicans Chuck Grassley, Orrin Hatch, Richard Shelby, Jim Inhofe, Pat Roberts and John McCain.